Pregled bibliografske jedinice broj: 1137329
Fréedericksz-Like Transition in a Biaxial Smectic- A Phase
Fréedericksz-Like Transition in a Biaxial Smectic- A Phase // Physical review. X, 11 (2021), 3; 031012, 25 doi:10.1103/physrevx.11.031012 (međunarodna recenzija, članak, znanstveni)
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Naslov
Fréedericksz-Like Transition in a Biaxial Smectic-
A Phase
Autori
Meyer, Claire ; Davidson, Patrick ; Constantin, Doru ; Sergan, Vassili ; Stoenescu, Daniel ; Knežević, Anamarija ; Dokli, Irena ; Lesac, Andreja ; Dozov, Ivan
Izvornik
Physical review. X (2160-3308) 11
(2021), 3;
031012, 25
Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni
Ključne riječi
Fréedericksz transition ; biaxial smectic- A phase ; bent-shaped dimers
Sažetak
The two main classes of liquid-crystal (LC) phases of rodlike molecules are nematics, where the rods align in the same direction (the nematic director n), and smectics, where the rods not only are aligned but also form layers. The electro-optic effects in LC devices that are a backbone in today’s display industry mainly use the Fréedericksz transition, which is the bulk reorientation of a surface-anchored nematic by an electric field. Conventional (uniaxial) smectics do not present a Fréedericksz transition, because, due to their layered structure, the director reorientation would distort the layers, which would cost too much energy. In a worldwide ongoing effort to extend the variety of LC compounds suitable for applications in the display industry, bent- shaped molecules have recently raised much attention, since they present multiple new LC phases with unusual properties. In this paper, we report on a structural and electro-optic study of the LC phases of a bent-shaped dimer. On cooling from the isotropic liquid, this compound shows a usual nematic (N), a twist- bend nematic (NTB), and a biaxial smectic-A phase (Sm Ab). Quite surprisingly, contrary to usual smectics, Sm Ab presents a remarkable electro-optic response, with low ( < 4 V) voltage threshold, no reorganization of the smectic layers, and low ( < 1 ms) response time (i.e., 30 times faster than the N phase at higher temperature). We interpret this unexpected electro-optic effect as a Fréedericksz transition affecting the secondary director m of the Sm Ab, and we model it by analogy with the usual Fréedericksz transition of the n director of the uniaxial N phase. Indeed, a Fréedericksz transition affecting only m in this biaxial fluid smectic does not alter its layered structure and costs little energy. From the point of view of applications, thanks to its low relaxation time, this “biaxial” Fréedericksz transition could be exploited in electro-optic devices that require fast switching.
Izvorni jezik
Engleski
Znanstvena područja
Fizika, Kemija, Interdisciplinarne prirodne znanosti
POVEZANOST RADA
Projekti:
HRZZ-IP-2019-04-7978 - Strukturna kiralnost vs molekulska kiralnost (SMChiral) (Lesac, Andreja, HRZZ - 2019-04) ( CroRIS)
Ustanove:
Institut "Ruđer Bošković", Zagreb
Poveznice na cjeloviti tekst rada:
Pristup cjelovitom tekstu rada doi journals.aps.org doi.org fulir.irb.hrCitiraj ovu publikaciju:
Časopis indeksira:
- Current Contents Connect (CCC)
- Web of Science Core Collection (WoSCC)
- Science Citation Index Expanded (SCI-EXP)
- SCI-EXP, SSCI i/ili A&HCI
- Scopus
- Nature Index